Datasheet TEA7532FP, TEA7532DP Datasheet (SGS Thomson Microelectronics)

.PROGRAMMABLEGAININ STEPSOF6 dB

.ON/OFFPOSITION

.LOWVOLTAGE

.POWER: 100 mWAT 5 V

DESCRIP TION

This16 pinsIC is designedfor monitor
(loudspeaker)telephoneset andprovides:

a) Signalamplificationformonitoring(loudspeaker)
b) Antiacousticfeedback(antilarsen)
c)Antidistortionbyautomaticgainadaptation
d) Antilarsenadjustment(full duplex)

BLOCK DI AG RAM

TEA7532

MONITOR AMPLIFIER

DIP 16

ORDERING NUMBERS : TEA7532DP(DIP16)

SO16

TEA7532FP(SO16)

July1993

1/16

TEA7532

PIN CONNECTI O N (Top view)

PIN DESCRIPTION

N° Symbol Description

1 ADJ Adjust Internal Reference V

LS

2 ALADJ Antilarsen Adjustement
3 ADS Antidistortion
4V

LS

Supply
5 MIC1 Microphone Input
6 MIC2 Microphone input
7 FAL Antilarsen Filter
8 TC1 Antilarsen Time Constant
9 INP Input Signal

10 LS1 Output Loudspeaker 1
11 V

REF

Internal Resistance

12 LS2 Output Loudspeaker 2
13 GND Ground
14

15
16

PG0
PG1

ON/OFF

Inputs Program Level to Loudspeaker

ABSOLUTE MAXIMUM RATINGS

Symbol Parameter Value Unit

T

op

V

LS

I

LS

V

Temperature Range –5 to + 45 °C
Supply Voltage 6 V
Supply Current for T > 300ms

for T ≤ 300ms

Voltage Level (pins, PG0, PG1, on/off) 0.6 > to VS+ 0.6 V

L

90

150

mA
mA

2/16

TEA7532

ELECTRICAL CHARACTERISTICS (T

=25oC, ILS= 30mA unless otherwisespecified)

amb

Symbol Parameter Test Conditions Min. Typ. Max. Unit

V

LS1

V

LSM

V

ADJ

G

G000
G001
G010
G011
G100

VLSSupply ILS= 2mA (fig. 7)

= 30mA (fig. 7)

I

LS

VLSMaximum I

=50µA (fig. 7 ; So = closed) 5.5 V

pin 1

Voltage Pin 1 ILS= 2mA to 30mA (fig. 7) 1.1 1.25 1.4 V

V

− V

10

Loudspeaker Amplifier Gain =

12

V

ON/OFF PG0 PG1

9

GND
GND
GND
GND

V

LS

GND
GND

V

LS

V

LS

X

GND

V

LS

GND

V

LS

X

2.6 3.0

12
18
24
30

THD Distortion f = 300Hz to 2kHz,

V

10–V12

G = G011, (fig. 8)

G2 [V(10) – V(12)]/V2 P

Z

MICIN

Z

INPIN

Z

V

OFFS

I

ON/OFF

I

PG0

I

PG1

I

ON/OFF

I

PG0

I

PG1

V

IL ON/OFF

V

IL PG0

V

IL PG1

V

IH ON/OFF

V

IH PG0

V

IH PG1

G

Microphone Input Symetrical at (pins 5-6)

Earphone Input (fig. 9) 2.2 2.8 3.4 kΩ
Antilarsen Adjustment Input 1 1.2 1.45 kΩ

IN2

Ouput Offset
[V

(10)–V(12)

]

Input Current ON State V

Input Current OFF State V

Input Voltage ON State 0.45

Input Voltage OFF State 1.5

Microphone Gain = V

MIC

(7)

/[V

(5)–V(6)

]

Vg Voltage Pin 8 0.48 0.67 0.75 V

G

Loudspeaker Attenuated

ATT

Gain = [V

(10)–V(12)

]/V

(9)

G0=PG1=VLS,V8

Asymetrical at (pin 6) fig. 9

G011 ; (fig. 8) – 50 50 mV

PG1

PG1=VLS

V

MIC

G011 ; V8= 0.6V ; (fig. 10)
G011 ; V

= 0.8V

= 0V ; (fig. 8) – 10

; (fig.8) 1

= 10mV

= 0.4V ; (fig. 10) 20

8

,

RMS

= 0.8V (fig. 8) 30 32 34 dB

–10
–10

1.5

1.5

, f = 2kHz (fig. 10)

RMS

22.5 23.5 24.5 dB

3.4

3.15

3.4VV

14

16

20

22

26

28

32

–30

34

–20

2%

4.5 kΩ

–5
–5
–5

1
1

0.45

0.45

–3030–20 dB

dB
dB
dB
dB
dB

µA
µA
µA

µA
µA
µA

V
V
V

V
V
V

dB

FUNCTIO NAL DESCRIPTI ON

TEA7532performs the followingfunctions:
Thecircuitamplifiesthe incomingsignaland feeds
itto the loudspeaker.PG0andPG1 inputsare used
to set the loudspeakergain in a range of 32dB to
14dBin 6dB steps.
The TEA7532inputs (PG0, PG1, ON/OFF) permit
the loudspeakertobe cut-offthus ensuringprivacy
of communication.

- The antilarsen (antiacousticfeedback)system is
incorporated.

- The maximum power available on a 50Ω imped­anceloudspeakeris25mWat3 volts and 100mW
at 5V.

Limitvaluesfor externalcomponents:
R3 min = 5 kΩ (R3 adjustVLS),R7 max= 390 kΩ,
R6 min = R7/35
Rmaxbetweenpin5 and6=10kΩ+C min= 10nF.

3/16

TEA7532

Figure 1 : LoudspeakerGain VersusVoltage on

Pin(3) - (8) with Pin2 Open.

(*) ATTENUATION =

Zin2(1.2 K) R2=10K⇒ATT = 20 dB

Zin2(1.2 K) + R2(EX T) R2=3 K⇒ATT ≈ 10 dB

Figure 3 : ACOutput VoltageVersusAmplifier

Gain.

Figure2 :LoudspeakerGain VersusVoltageon

Pin(3) - (8)and VersusR

.(*)

2

Figure4 : Power Availableon Loudspeaker

VersusV

Typical Curve.

LS

Figure 5 : DistortionVersus Output Power. Figure6 : OutputPowerVersusSupplyCurrent.

4/16

TEST CIRCUI TS
Figure 7 : ShuntvoltageRegulator/Reference

Voltageat Pin 1.

TEA7532

Figure8 : LoudspeakerAmplifier :Gain/Distor

tion/OutputOffset.

S1 S2 S3

G1XX 1 X X

G000 0 0 0
G010 0 1 0
G001 0 0 1

Note : S0 open for VLS 1

S0 close for VLSM.

Figure 9 : ImpedanceZMIC, ZINP andZin2.

V (10)– V (12) V

• G= =

• VOFFS with Vin = 0.

V

LS

G

ND

V (9) V (9)

=1

=0

out

Figure10 : AntiacousticFeedbackSystem at

G011.

Zmic = ; Zinp = ; Zin2 =

1.1V 1.1V 1.1V
I6 I9 I2

5/16

TEA7532

CIRCUIT DESCRI PTION

TEA7532isa 16pin DILintegratedcircuitproviding
the following facilities:

Loudspeakeramplifier

-

1.1. LOUDSPEAKERAMPLIFIER

Figure 11.

Antiacousticfeed-backsystem

-

(antilarsensystem)

Theamplifieris dividedinto 3 mainsections.

AutomaticGain Control (AGC)

-

Preamplifier

-

Push-pullamplifier (bridgestructure)

-

a) The AGC section is used for the antilarsenand
antidistortionsystem.

• Whenusedina telephonesettoavoidlarsenef-

fect the AGC automatically decreases loud­speakeramplifiergain.

• When the required output level exceeds the
capabilities of the available current, the AGC

Figure 12.

decreases the loudspeaker amplifier gain to
avoiddistortion.

b) The preamplifier permitsstepcontrolof amplifier
gain in steps of 6 dB, using pins PG0 and PG1,
which maybe controlledusingswitchesor bya mi­croprocessor.Theamplifiermaybemutedusingthe
ON/OFFcontrolsignal (pin16).

c)Theoutputamplifierusesa doublepush-pullcon­figuration(Hbridge)togetmaximumdynamicrange
underlimited supplyconditions.

6/16

TEA7532

Amplifierdc supply.

Intransmissionmode,the supplyvoltageis control­ledby theinternalshunt DC regulator.Forthis rea­son,theTEA7532shouldbesuppliedfromacurrent
source

Figure 13.

(see: supplyconsiderations).
An antidistortion system is embodied which pro­vides AGC control to avoid loudspeakerdistortion
undercurrent-limitedconditions.

Circuitaction.

Whenthe supplyvoltageis insufficient,thevoltage
at pin1, fallsbelowthereferencevoltage1.1 V,re­sultingintransistor(TR)beingswitchedoff,resulting
in zero currentflowin resistorR. This stateenables
thegaincontrolsystem.Undertheseconditions,the
shuntDC supplywill switchat a ratedeterminedby
the time constantof theRC network onpin 3.
This switchingactionaccomodatesnormal speech

Figure 14 .

characteristicsunderlow supplyconditions.

1.2. ANTIACOUSTIC FEED-BACK SYSTEM(AN­TILARSENSYSTEM)

Thepurposeof thissystemisto controlAGCaction
in order to avoid acoustic feed-back between the
loudspeakerand the microphone, when used in a
telephoneset.

7/16

TEA7532

Principle of operation.

When examiningthe spectral density of the voice
area and the larsen area, it can be seen that the

Figure15.

dominant features of each exist in different fre­quencybands.

To extract the larsen component, the microphone
signalisfirstfilteredbya secondorderfilter(formed

Figure 16.

Zin : 4 kΩ

A= =15

V7

V5 – V6

by two first orderfilters),thenamplifiedand rectified
in orderto producetheAGC control signal.

Thefirst filter is generatedby the capacitorson pins 5 and 6 ; the secondfilterby theR-C network on pin 7.

8/16

Figure 17 : AntilarsenSystem FilterResponse.

Filteron pins5 & 6

f2 =

C9 + C10

2π ZinC9 C10

Filteron pin7

f1 =

f3 =

1

2π (R5+ R6)C5

1

2π R5C5

TEA7532

Antilarsensystem
Filter response

If f2 = f3 the Antilarsensystemfilteris equivalent
to a secondorder filter.

C9 +C10 1

2π ZinC9 C10 2π R5C5

=

9/16

TEA7532

A complete telephone set has two antilarsen
systems:

one in the transmission circuit(for example :

-

TEA7051)antisidetonenetwork ;

Figure 18.

one in the loudspeakeramplifier

-

(forexample: TEA7532).
Together these form a high efficiency antilarsen
system.

PIN FUNCTI ONS
PIN 1 : ADJUSTV

Thispin is used to adjustthe ICsupplyvoltage.
PIN 2 : ANTILARSENADJUSTMENT

The AC signal at this pin is amplified to the loud­speakerwithout AGCattenuation.

10/16

LS

PIN 3 : AUTOMATICGAINCONTROL FILTER
The antidistortion system responseis adjusted by
the R-C networkon thispin.
TheAGCwillbe switchedON when thelevelon pin
3isgreaterthanthereferencevoltage(0.4V),theRC­networkcharges(current sourceON) or discharges
(currentsourceOFF)accor dingto thesupplyvoltage.

THEORETICAL VOLTAGE ON PIN 3
Figure 19 :

Figure 20.

TEA7532

Thevalue ofR affects the systemtime constant

-

and the charge/dischargeduty cycle.
Thevalueof C onlyaffectsthe systemtimecon-

-

stant.
Rshouldbegreateror equalthan150kΩ forcor-

-

rect AGC operation.

PIN 4 : CIRCUIT SUPPLYVOLTAGE
Withpin1 opencircuit,VLSisinternallystabilizedat

2.8 V.

Whenthe TE A7532isunderAGC control,thevoltage
onthispinvariesslightly(dueto AGCaction).

11/16

TEA7532

PIN 5/6 : MICROPHONEINPUTS

Theseare used for antilarsencontrol.
PIN 7 : ANTILARSENFILTER1

Thesecondfilterof the antilarsensystem (1 st filter
: pins 5-6)is formed by the RC networkR5C5.
In order to obtain a secondorder filter for the anti­larsensystem, the cut-offfrequencydefinedat this
pin,shouldbe the same as that chosen for the first
filter.

For correct TEA7532 operation R6 and R5 should
be fixed at10 kΩ and 1 kΩ respectively.

PIN 8 : ANTILARSENFILTER2
Thegainandtheresponseofthe antilarsensystem

canbeadjustedrespectivelyby theresistorandthe
capacitoronthispin,accordingtotheacousticchar­acteristicsof thetelephoneset.

Thevalueoftheresistorshouldnotexceed390kΩ.
Whenthevoltageonthispin exceedsthe threshold
voltageof 0.4 V, the AGCsystemis enabled.

Figure 21.

PIN 9 : EARPHONEINPUT

Inputfor loudspeakersignal.
PIN 10-12 : LOUDSPEAKEROUTPUTS

Maximumoutput voltage : V

=2VLS-2.5 V (with

pp

a gainof 32 dB).
Maximumoutput current: dependingof the supply

current.
Twoloudspeakerconnectionmethodsarepossible,

usingthe amplifierin either”H” mode or ”B” mode.
Note : It is advisable to connecta 47nF capacitor

in parallel with the loudspeaker (between
pins10 and12).

-”H”Mode

Thisisforlowvoltageworking,butatahighersupply
current.The highestoutputpoweris availableinthis
mode,dueto the 5.5V maximumsupplyvoltagere­striction,imposedby the TEA7532.
Loudspeakerimpedancerecom mendedvalue:50Ω.
Maximum gain available between earphone input
andloudspeakeroutput: 32 dB.

Figure 22.

12/16

TEA7532

- ”B” Mode

Thisallowshighervoltageoperation,but at a lower
supplycurrent.
Loudspeakerimpedancerecommendedvalue:25Ω.
Maximum gain available between earphone input
and loudspeakeroutput: 32 - 6 = 26 dB.

Figure 23.

PIN 13 : GROUND
PIN 14-15 : GAINADJUSTMENTINPUTS

Thesepinsare usedto adjustthe loudspeakeram­plifier gain.Foursteps of 6 dB/stepare available
(pinopen circuit = high level).

PIN 11 : Vref :INTERNAL REFERENCE
Outputwhich providesaninternallyregulatedrefer­ence voltage.

Vref =1.1 V typical
MAXIMUMAVAILABLECURRENT :5 µA

PG0 PG1

1 1 Gmax
1 0 Gmax - <0> 6 dB
0 1 Gmax - 12 dB
0 0 Gmax - 18 dB

PIN 16 : LOUDSPEAKERMUTING.
Thispinis used to mutethe loudspeaker.Pinopen-

circuit: high level= loudspeakermuted.
Pinlow level: louspeakerenabled(see connection

of pins14 and15).

13/16

TEA7532

DIP16 PACKAGE MECHANICAL DATA

DIM.

Min. Typ. Max. Min. Typ. Max.

a1 0.51 0.020

B 0.77 1.65 0.030 0.065
b 0.5 0.020

b1 0.25 0.010

D 20 0.787
E 8.5 0.335
e 2.54 0.100

e3 17.78 0.700

F 7.1 0.280

i 5.1 0.201
L 3.3 0.130
Z 1.27 0.050

mm inch

DIP16.TBL

b

Z

16

18

14/16

a1

I

L

Be

e3

D

9

F

b1

E

PM-DIP16.EPS

SO16 PACKAGE MECHANICAL DATA

Dimensions

Min. Typ. Max. Min. Typ. Max.

A 1.75 0.069

a1 0.1 0.2 0.004 0.008
a2 1.6 0.063

b 0.35 0.46 0.014 0.018

b1 0.19 0.25 0.007 0.010

C 0.5 0.020

c1 45

D 9.8 10 0.386 0.394
E 5.8 6.2 0.228 0.244
e 1.27 0.050

e3 8.89 0.350

F 3.8 4.0 0.150 0.157

G 4.6 5.3 0.181 0.209

L 0.5 1.27 0.020 0.050

M 0.62 0.024

S8

Millimeters Inches

o

(typ.)

o

(max.)

TEA7532

SO16.TBL

A

a2

b

e

s

e3

D

M

16 9

F

18

GL

a1

c1

b1

C

E

PM-SO16.EPS

15/16

TEA7532

Information furnished is believed to be accurate and reliable. However, SGS-THOMSON Microelectronics assumes no responsibility for
the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its
use. No license is granted by implication or otherwise under any patent or patent rights of SGS-THOMSON Microelectronics. Specifica­tions mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information pre­viously supplied. SGS-THOMSON Microelectronics products are not authorized for use as critical components in life support devices or
systems without express written approval of SGS-THOMSON Microelectronics.

 1994 SGS-THOMSON Microelectronics - All Rights Reserved

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